In optical systems, and in particular in imaging systems, such as thermal cameras, it is needed to provide a shutter that can be placed in front of the imaging sensor and block its view when desired. In an Infra-Red (IR) camera a shutter is provided for occasional calibration of the imaging sensor, or for preventing undesired irradiation from reaching the imaging sensor.
Calibration is necessary in thermal sensors in order to ensure accurate measurements and to obtain correct images. Calibration is especially important in IR cameras, which have a thermal sensor that is not cooled to supercool temperatures.
Every once in a while a uniform surface of a black body is placed in front of the sensor and the sensor matrix is calibrated to measure a surface of uniform temperature.
There are known IR cameras, which include such an optical shutter. Typically the shutter comprises a black painted plate, which is displaced between two positions in front of the sensor—a blocking position in front of the sensor view and a retracted position, where the shutter is removed from the sensor's field of view.
A known shutter mechanism includes a shutter plate turning about a motor axis to and out of the blocking position. Another shutter mechanism includes a shutter plate coupled to a motor with linear transmission so as to facilitate linear motion of the shutter between the two positions.
In some cases it is desired to have a shutter mechanism that is silent in order to prevent exposing the existence and location of the imaging system.
It is an object of the present invention to provide a shutter mechanism for imaging systems, which electromechanically activated.
Another object of the present invention is to provide a shutter mechanism for imaging systems, which is silent.
Yet another object of the present invention is to provide a shutter mechanism for imaging systems, which is reliable, holding the shutter plate in either of its positions firmly and stably.
Other advantages and objects of the present invention will become apparent after reading the present specification and reviewing the accompanying figures.